/**
 * Convert a single file-input element into a 'multiple' input list
 *
 * Usage:
 *
 *   1. Create a file input element (no name)
 *      eg. <input type="file" id="first_file_element">
 *
 *   2. Create a DIV for the output to be written to
 *      eg. <div id="files_list"></div>
 *
 *   3. Instantiate a MultiSelector object, passing in the DIV and an (optional) maximum number of files
 *      eg. var multi_selector = new MultiSelector( document.getElementById( 'files_list' ), 3 );
 *
 *   4. Add the first element
 *      eg. multi_selector.addElement( document.getElementById( 'first_file_element' ) );
 *
 *   5. That's it.
 *
 *   You might (will) want to play around with the addListRow() method to make the output prettier.
 *
 *   You might also want to change the line 
 *       element.name = 'file_' + this.count;
 *   ...to a naming convention that makes more sense to you.
 * 
 * Licence:
 *   Use this however/wherever you like, just don't blame me if it breaks anything.
 *
 * Credit:
 *   If you're nice, you'll leave this bit:
 *  
 *   Class by Stickman -- http://www.the-stickman.com
 *      with thanks to:
 *      [for Safari fixes]
 *         Luis Torrefranca -- http://www.law.pitt.edu
 *         and
 *         Shawn Parker & John Pennypacker -- http://www.fuzzycoconut.com
 *      [for duplicate name bug]
 *         'neal'
 */
function MultiSelector( list_target, max ){

	// Where to write the list
	this.list_target = list_target;
	// How many elements?
	this.count = 0;
	// How many elements?
	this.id = 0;
	// Is there a maximum?
	if( max ){
		this.max = max;
	} else {
		this.max = -1;
	};
	
	/**
	 * Add a new file input element
	 */
	this.addElement = function( element ){
		
		// Make sure it's a file input element
			if( element.tagName == 'INPUT' && element.type == 'file' ){
	
				// Element name -- what number am I?
				element.name = 'file_' + this.id++;
	
				// Add reference to this object
				element.multi_selector = this;
	
				// What to do when a file is selected
				element.onchange = function(){
	
					// New file input
					var new_element = document.createElement( 'input' );
					new_element.type = 'file';
	
					// Add new element
					this.parentNode.insertBefore( new_element, this );
	
					// Apply 'update' to element
					this.multi_selector.addElement( new_element );
	
					// Update list
					this.multi_selector.addListRow( this );
	
					// Hide this: we can't use display:none because Safari doesn't like it
					this.style.position = 'absolute';
					this.style.left = '-1000px';
	
				};
				// If we've reached maximum number, disable input element
				if( this.max != -1 && this.count >= this.max ){
					element.disabled = true;
				};
	
				// File element counter
				this.count++;
				// Most recent element
				this.current_element = element;
				
			} else {
				// This can only be applied to file input elements!
				alert( 'Error: not a file input element' );
			};
	};

	/**
	 * Add a new row to the list of files
	 */
	this.addListRow = function( element ){
		var fileext=element.value.substring(element.value.lastIndexOf("."),element.value.length)
		fileext=fileext.toLowerCase();
		if ((fileext!='.jpg')&&(fileext!='.gif')&&(fileext!='.jpeg')&&(fileext!='.png')&&(fileext!='.bmp')){
			alert("Sorry! Only support JPG,JPEG,GIF,PNG  ");
			element.focus();
    }else{

		// Row div
		var new_row = document.createElement( 'div' );
		
		// Delete button
		var new_row_button = document.createElement( 'input' );
		new_row_button.type = 'button';
		new_row_button.value = 'Delete';
		new_row_button.className='delButton';

		// References
		new_row.element = element;

		// Delete function
		new_row_button.onclick= function(){

			// Remove element from form
			this.parentNode.element.parentNode.removeChild( this.parentNode.element );

			// Remove this row from the list
			this.parentNode.parentNode.removeChild( this.parentNode );

			// Decrement counter
			this.parentNode.element.multi_selector.count--;

			// Re-enable input element (if it's disabled)
			this.parentNode.element.multi_selector.current_element.disabled = false;

			// Appease Safari
			//    without it Safari wants to reload the browser window
			//    which nixes your already queued uploads
			return false;
		};

		// Set row value
		if(is_ie != '0'){
			new_row.className='list';
			new_row.innerHTML = "<img src='"+element.value+"' onload='GetSize(this)'>";
		}else{
			new_row.className='rows';
			new_row.innerHTML = element.value	;
		}
		// Add button
		new_row.appendChild( new_row_button );

		// Add it to the list
		this.list_target.appendChild( new_row );
		};
	};

};